Extreme tolerance requirements in lens-making necessitate a special machine design

14, G. M. Zhang, S. G. Kapoor, "Dynamic generation of machined surfaces, Part 2. Construction of surface topography," Journal of Engineering for Industry, Transactions of the ASME, 113(2), pp. 145-153. (May 1991). In Part 1 of these two-part papers, a normal distribution model has been formulated to describe the random excitation system present during machining. Part 2 presents a methodology to dynamically generate the surface topography under the random excitation environment through computer simulation. The proposed methodology uses the tool vibratory motion along with the tool geometrical motion to construct the topography of a machined surface. Both experimental and simulation results confirm that when a small feed is used, the influence of the spiral trajectory of tool geometrical motion on the surface generation decays dramatically and the random excitation system, on the opposite, is strengthened playing a significant role in surface texture generation.10 Refs. Index Terms: metal cutting-surfaces; dynamics; computer simulation; cutting tools-vibrations; surfacesroughness measurement; machined surface dynamics; surface topography; random excitation systems; tool vibratory motion; parametric tool path equations; cutting parameter feed. 15, S. N. Shatokhin, Y. A. Pikalov, V. I. Shakhvorostov, "Dynamometric uses of adaptive aerostatic bearings," Measurement Techniques, 33(3), pp. 215-217. (Aug 1990). Automatic cutting-tool diagnosis with adaptive control for the size adjustment and machining mode can provide a promising way of improving the accuracy and throughput in a numericallycontrolled metal-cutting machine. Such a system requires ongoing information on the changes in all or at least the most important components of the cutting force. Another way of improving machines, particularly fast and precision ones, is the use of aerostatic bearings in the spindles. However, the traditional designs for such bearings with passive flow compensation have poor load characteristics because of the restricted compressed air pressure. Adaptive aerostatic bearing sensors have been devised at Krasnoyarsk Polytechnical Institute to handle these tasks. They differ from traditional designs in that there is feed back to the air flow when the load changes, which provides a marked improvement in the load characteristic. 5 Refs. Index Terms: mechanical variables measurement-forces; metal cutting-force measurement; dynamometers-applications; bearings-air lubricated; aerostatic bearings; passive flow; cyclical control. 16, B. Haack, M. Tomizuka, "Effect of adding zeroes to feedforward controllers," Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME, 113(1), pp. 6-10. (Mar 1991). The effect of adding zeroes to two types of feedforward controllers, stable pole zero cancelling (SPZC) controllers and zero phase error tracking (ZPET) controllers, is discussed. When there are uncancellable zeroes in the feedback system, additional zeroes in the feedforward controller can reduce the tracking and; or the contour error. For multi-axis contouring with mismatched axis dynamics, a ZPET controller cancels the phase error and provides good contouring accuracy. With a SPZC controller which does not cancel the phase lag, the axes can be 'matched' for equal phase lag by adding zeroes to the feedforward controller. 14 Refs. Index Terms: control systems; dynamics; metal cutting-control systems; feedforward controller; zero phase error tracking (ZPET) controller; stable pole zero cancelling (SPZC) controllers; mismatched axis dynamics; error cancelling filter; tracking control. 17, M. Rahman, M. A. Matin, "Effect of tool nose radius on the stability of turning processes," Journal of Materials Processing Technology, 26(1), pp. 13-21. (May 1991). Among various machining parameters, tool signature has a significant contribution to the cutting dynamics and stability of a machining process. In this study, both static and cutting tests have been carried out to investigate the effect of the tool nose radius on the stability of a cutting process. The results of both types of tests have good qualitative agreement. A theoretical analysis has further substantiated the results. 13 Refs. Index Terms: cutting tools; metals and alloys-machining; tool nose radius; damping factor. 18, H. Notoya, S. Yamada, Y. Takatsuji, I. Tsukuda, H. Mizutani, "Effects of mechanical properties on machinability of various aluminum alloys," Journal of Japan Institute of Light Metals, (March 1991). Various aluminum alloys (2011-T8, 3003-H14, 4032-T6, 5056-H14, G67-T6, 7075-T6 and AI-17%Si-T6) were turned with K10 and diamond compact tools to examine the cutting behavior under wide range of cutting conditions. The effects of mechanical properties (hardness, tensile strength shear stress of high temperature and coefficient of friction for K10 tool against work materials) of these alloys on cutting forces, chip forms and finished surface roughness were discussed. Chip forms and cutting forces depended on the coefficient of friction on the rake face of K10 tool at high temperature. Cutting forces and chip forms cut with diamond compact tool differed from those with K10 tool. Index Terms: aluminium alloys; elongation; friction; hardness; machining; surface topography; yield strength; friction coefficient; yield strength; elongation; mechanical properties; machinability; hardness; tensile strength; shear stress; surface roughness; AI-Cu-Fe; AI-Si-Cu; AI-Mn-Fe; AI-MgFe; AI-Mg-Si; AI-Z n-Mg. 19, N. J. Brown, J. S. Taylor, B. A. Fuchs, "Experiences with polishing electroless nickel," (Lawrence Livermore National Lab., CA, Apr 1991). 31 pages. (UCRL-JC-106864). During recent years the bureaucracy has become increasingly rigid in demanding a mechanical observance of the minimum bid specified on the simplest terms. Qualifications of the vendor and specifications of the product are increasingly viewed as attempts to thwart the progress of the process toward minimum quality, Any such qualification or specification must be justified as to not only reasonableness but necessity. This provides the purpose of this paper, to record forever the existence of the wild dingleberry and to disclose its habits with respect to laps and the marvelous effects it has on the emotional state of the lappers. Among metal polishers, the term dingleberry refers to a type of nodule or wartlike structure sometimes seen in isolation and occasionally in considerable profusion particularly in chemically plated surfaces. 2 refs. Index Terms: nickel-polishing; abrasives; defects; inclusions; plating; deposition; elements; metals; surface coating; surface finishing; transition elements. 20, R. Wada, "Extreme tolerance requirements in lens-making necessitate a special machine design," Werkstatt und Betrieb, 124(6), pp. 470-472. (Jun 1991). In the electric and optical industries, highprecision lenses of spherical or non-spherical shape are made efficiently in large-bath production using metal moulds. The materials used for PRECISION ENGINEERING

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these lenses are plastics or various types of glass. However, metal moulds for glass lenses have a short production life only, and therefore a large number of moulds is required. As a consequence, there has been a continuous increase in demand for productive manufacturing processes. This is why a high-precision CNC machine with an integrated measuring system was developed for machining non-spherical surfaces. In German. Index Terms: machine design; fits and tolerances; machine tools-control systems; control systems, numerical-applications; high-precision machine tool; CNC machine tool; lens-making tolerance; nonspherical surface machining; integrated measuring system. 21, D. Gallagher, W. Cash, J. Green, "Fabrication of a grazing incidence telescope by grinding and polishing techniques on aluminum," Proceedings of SPIE - X-Ray; EUV Optics for Astronomy, Microscopy, Polarimetry, and Projection Lithography, Vol 1343, Jul 9-13, 1990. pp. 155-161. The International Society for Optical Engineering. Bellingham, WA. A Wolter type-I grazing incidence telescope is currently under construction at the University of Colorado, Boulder. The telescope mirrors were fabricated by machining on a lathe to approximately 1-2 arcminutes quality and ground and polished to improve their figures. Current measurement of the telescope's image quality gives a FWHM measurement of 44 arcseconds. We hope to achieve 5-10 arcsecond quality when completed. 4 Refs. Index Terms: telescopes-materials; aluminum and alloys-applications; mirrors-applications; grinding-applications; polishing-applications; grazing incidence telescope; image quality measurement; Ronchi test. 22, F. Uchida, S. Moriyama, Y. Suzuki, "Fabrication of aspheric mirrors for a hard X-ray microprobe," Journal of the Japan Society of Precision Engineering, (Feb. 1991 ). The authors describe the fabrication of aspheric mirrors for an X-ray microprobe which is available on scanning X-ray microscopy and a local area X-ray analysis. New X-ray microprobe optics, which improve spherical aberration of spherical mirror optics (Kirkpatrick-Baez optics), is constructed by a pair of elliptic cylinder mirrors. These mirrors are fabricated by a numerically controlled diamond flycutting machine where tool cutting depth is dynamically controlled synchronizing to tool rotational angle. These mirrors have achieved a contour accuracy of 0.05 l~m and a surface roughness of 1 nm which satisfies hard X-ray reflecting conditions. A focused X-ray spot of 4.2 x 5.5 I~m was obtained at a wavelength of 2.0 AA using synchrotron radiation from the KEK Photon Factory 2.5 GeV storage ring. Index Terms: cutting; mirrors; numerical control; spatial variables control; X-ray apparatus; X-ray chemical analysis; X-ray optics; aspheric mirrors; hard X-ray microprobe; scanning X-ray microscopy; X-ray analysis; spherical mirror optics; Kirkpatrick-Baez optics; elliptic cylinder mirrors; numerically controlled diamond flycutting machine; tool cutting depth; contour accuracy; surface roughness; focused X-ray spot; synchrotron radiation; KEK Photon Factory 2.5 GeV storage ring. 23, L. A. Grant, R. E. Hardesty, "Fabrication of stable lightweight beryllium optical support structures," Proceedings of SPIE - Dimensional Stability, Vol 1335, Jul 12-13, 1990. pp. 140-155. Int Soc for Optical Engineering. Bellingham, WA. This paper will describe many recent aerospace applications where beryllium was successfully used in different types of optical support structures. It discusses how several manufacturing methods, including machining, metallurgical brazing, epoxy bonding and near-net-shape processing were used to produce the desired overall configurations. The installation of non-beryllium inserts is also discussed in detail. Typically made of titanium, these inserts allow the end user to final finish mechanical attach points and optical lapping points, thus circumventing potential toxicity hazards associated with airborne beryllium particles. Data is also presented about the stress and stability characteristics in some of the more specialized applications, as well as weight and stiffness. 12 Refs. Index Terms: beryllium and alloys-space applications; epoxy resins-bonding; optical systems-materials; titanium and alloys-space applications; brazing-applications; lightweight beryllium optical support structures; metallurgical brazing; machining; near-net-shape processing. 24, A. Ahmad, "Fabrication techniques for high resolution lens assemblies," Proceedings of SPIE - Dimensional Stability, Vol 1335, pp. 194-198. Int Soc for Optical Engineering. Bellingham, WA. This paper presents the fabrication and assembly techniques for high resolution lens assemblies such as the projection lenses used for submicrometer photolithography. In order to meet the stringent precision and dimensional stability requirements for such lens assemblies, the aluminum lens cells are machined and heat treated in several steps to achieve the required accuracies. Special optical tools and mechanical gages are then used to assemble the lenses into the cells on an air bearing table. 3 Refs. Index Terms: lenses-machining; aluminum and alloys-applications; high resolution lens assemblies; dimensional stability; lens cells fabrication; optical tools. 25, L. P. Solov'eva, S. N. Nocharskii, L. I. Krynskaya, "Finish lapping of ballscrew and nut threads," Soviet Engineering Research, 10(4), pp. 106-107. (1990). A team of Odessa Polytechnic has developed and investigated a method of lapping semicircular thread profiles of ballscrew drives. The method is recommended for use as a finishing operation in forming the threads. To study the feasibility of lapping ballscrew thread profiles, lapping tests were conducted, with rates varying in accordance with a test planning matrix. The test specimens were 63 mm diameter ballscrew nuts with a pitch of 10 ram, ground by the method employed at the Mikron Combine (Odessa). Nut material was 9KHS steel (HRC 60-62). The tests were carried out in a special semiauto, the gearing system of which permitted the working and ancillary motions of the stones to be varied. Lapping occurs as a result of a complex motion. 3 Refs. Index Terms: mechanical drive-lapping; lapping machines-feeding; screw threads-lapping; thread LAPPING; ballscrews; abrasive grains. 26, Y. Koren, T. Ko, A. Galip Ulsoy, K. Danai, "Flank wear estimation under varying cutting conditions," Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME, 113(2), pp. 300-307. (Jun 1991). A model-based methodology, designed to operate under varying cutting conditions, for on-line estimation of flank-wear rate based on cutting force measurements is introduced. The key idea is to employ a model of the relationship between force and flank wear, together with on-line parameter estimation methods. This permits separation of the direct effect of changing cutting conditions on force from the indirect effect where changing cutting conditions affect the wear which, in turn, affects the force. Simulation results confirm the effectiveness of this strategy for turning with varying speed, feed, or depth of cut. Experiments, 56

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